Process of grinding toothed articles



April 8, 1930. F. J. LAMBORN PROCESS OF GRINDING TOOTHED ARTICLES Filed March 7, 1923 TTORNEYS Patented Apr. 8, 1930 UNITED STATES PATIENT, OFFICE,

FRED J. LAMBORN, or'nnrnoir, ionrean, ASSIGNOR, BY MESNE nssrsmvinnrs, T

CHRYSLER CORPORATION, A CORPORATION. OF DELAWARE PROCESS OF GRINDING TOOTHED ARTICLES Application filed March 7, 1923. Serial No. 623,328.

This invention relates to a process of grinding a toothed article and to the article so ground.

It often is desirable to grind certain segments of toothed articles such as splined shafts and the like, so that only certain segments thereof shall be ground while other segments are left in the milled or other relatively unfinished condition. For example, in the case of a splined shaft it may be desirable only to grind the valley portions, that is, the cylindrical portion between the splines. Various expedients for grinding such internal sur-' faces have been tried. In the so-called formgrinding, a grinding wheel is provided whose face is formed complementary to the entire segment to be ground and the entire face of such segment is finished in one pass of the wheel longitudinally of this segment, and 2 before the succeeding segment is operatedis not limited to this particular operation, but

may be employed in the grinding ofother toothed articles, and may be applied to the grinding of otherportions of such articles.

In the present application there is'illus- 40 trated and described a method of generative grinding which may be utilized to act successively upon the successive curved segments to be ground and gradually develop the desired shape of thearticle, and, if desired, without necessitating the finishing-of an entire segment before a successive segment is operated upon. The Thomas Patent No. 1,252,509 sets forth a method of generative grinding, but various objections to it will be evident to those skilled in the. art. By the present invention these objections are overcome. For

the purpose of. illustration and not as a limitation, the method will be described as carried out for the grinding of the cylindrical valley portions only of a shaft provided with integral splines.

In the drawings, which are merely illustrative of'the method, Fig. 1 is a side elevation of a splined'shaft in contact with the grinding wheel shown broken away in side'- elevation;

Figs. 2, 3 and 4: are details;

Fig. 5 isa-perspective view of a grinding wheel which may be used; and

- Figs. 6 and 7 illustrate amodified construction which may be used.

1 indicates the shaft provided with splines 2 to 5 between which are curved segments de sired to be ground, such as the valley portion or'segment 6. Relief grooves, such as 7 at the base of the splines may be provided if desired, The shaft is suitably mounted and held so that it may be positively rotated at any de sired speed, and, in the case of an article such as along shaft, so that it may besimultaneously' moved longitudinally of its axis as indicated by the arrow atthe right in Fig. 1

The grinding wheel 8 is provided and mounted to rotate on a transverse axis, that is, on an axis transverse, and preferably at substantially a right angle, to the axis of the shaft.

It is driven by suitable mechanism not shown.

The grinding face which contacts with the valley portion 6 ispreferably flat, as indi-' cated at 9 in Fig. 2. It contacts tangentially with the curved surface 6 as it touches the surface only atsubstantially one point, see Figs. 1 and" 2.

" It will be obvious that if the shaft is then rotated in the direction of the arrow and the grinding wheel is also rotated, the grinding face will travel relatively over the surface 6 and grind it to'the' shape desired. But some provision for allowing the grinding wheel to skip the advancing spline or allow the latter topass Inustbe provided. This may be accomplished, without moving either the shaft or the grinding wheel bodily away from the other, by shaping the grinding wheel with a cut-away portion such as will allow the sucing wheel has just engaged the leading edge. of the surface 6. When the shaft has rotated to the position shown in Fig. 8, the shaft has.

rolled relatively over the grinding. face 9 which has then moved relatively toward the left, as indicated. \Vhen the shaft has rotated to the position indicated in Fig. 4, the

grinding face has moved relatively furtherto the left, due to the pitch of the-helical groove, thus allowing the spline or tooth 2 to enter the groove 10. As the shaft and wheel continue to revolve, the spline will move in this groove until it clears the same, as indicated by the spline 3 in Fig. 3. A. similar segment 12 will then engage the face of'the grinding wheel andthe operationwill be re peated on this successive segment. The other valley segments 13 and la will similarly be ground.

It will be observed that in this operation it is unnecessary to move bodily either the shaftor the grinding wheel away from the other.

They retain their relative bodily positions at all times. v 1

. In order that the wheel may contact with the shaft throughout its length, the oneshould be moved relatively to the other axially of the. shaft. It is preferable to move the shaft bodily and longitudinally of its axis during the grinding operation. By so positively rotating both the shaft and the grinding wheel and slowlymoviug the shaft axially of itself, the contact point between the wheel and shaft is caused to travel over the valley portions in a helix or spiral of very low pitch. By making the grinding wheel of-relatively large diameter compared with that of the shaft, the curve of the wheel at the point of contact is quite gradual and consequently the wheel makes grinding contact with theshaft in a relatively broad line, and if the shaft is moved axially quite slowly, the surface will be generated quite smooth and of great accuracy. r

It will be obvious that the grinding wheel, where it contacts with the shaft, moves longitudinally of the shaft and consequently the lines of abrasive are longitudinal of the shaft. Such lines are difiicult to reproduce in drawing but are indicated by15 in Fig. 1. The helical line of abrasive contact between the wheel and shaft is indicated at 16, although it must of course be understood that such helical line is only faintly distinguishable upon the ground shaft itself when a wheel of relatively large diameter is used. A grinding wheel substantially one foot in diameter operating upon a splined shaft about one and one-eighth inches in diameteracross valley portions has been successful. The pitch of the helical groove in the grinding wheel which should be used will of course depend upon the angular speed of rotation of the splined shaft. These may easilybe worked out by any mechanic.

Figs. 6 and 7" show a modification which may be used. In this a grinding wheel 17 having a cylindrical and non-helical face is shown with a. portion -18.cut away to clear the splines, as indicated by the-spline 19. The f remainder of the wheel, such as 20, is ofsuch;

diameter as will contact with the valley;.portion. When the shaft andjgrinding wheel are rotated at the proper relative. angular: speeds, the cutaway-portion 18 will allow the.

spline to pass and the remainder of thewheel to grind the curved valley-portion aswill obvious.

Various advantages;- of this methodof grinding will be obvious to thoseskilled inthe art, and it'will be evidentthatthe method. herein disclosed obviatesm-anyof the: objec tions to prior known methods.

It is recognized that'this-methodis' susceptible of utilization ina variety ofways and for the grindingo-fvarious surfaces on different: forms of toothed articles. claims are therefore notli-mi-ted to the particular steps or embodiments which have been above set forth: merely as ill-ustrativeexs amples.

What I claim is:

1. The process of grinding splinedshafts.

which comprises positively rotating asplined shaft with its valley portion in contactwith;

the helically formed peripheral grinding face of a rotatingegrinding wheel arranged hob having its grinding surface formed :as a helix, with its axis transverse to that of the shaft, and rotating the said shaft directly as 3. The process of grinding splineshafts,

which consists in subjecting-a splined and hardened shaft to the action ofian abrasive hob having its grinding. surface formed as or The helix with its axis transverse to that of the shaft, rotating the said shaft directly as distinct from by the worm action of the helical grinding surface to present different surfaces in succession to the abrasive hob with each rotation of the latter, and advancing the shaft toward the hob during the correcting operation. 7

4. The process of grinding toothed articles having series of teeth arranged in an arc, which comprises placing the article in grinding contact with a grinding wheel having a peripheral portion thereof cut away to allow the teeth to pass, and arranged with its axis transverse to the axis of the article, moving relatively the grinding wheel and articleto transfer the point of contact in the general I direction of the axis of said arc, and turning relatively the article and wheel substantially about the axis of said are other than by the contact of the wheel with the article and in timed relation to the rotation of the wheel to carry the teeth of the article successively through the cutaway portion of the wheel.

5. The process of grinding toothed articles having a circular series of teeth, which comprises placing the article in grinding contact with a grinding wheel having a peripheral portion thereof cut away to allow the teeth to pass, and arranged with its axis transverse to the axis of the article, moving the article. to transfer the point of contact in the direction of the axis of the article, and turning the article about the axis thereof other than by the contact of the wheel with the article, and in timed relation to the rotation of the wheel to carry the teeth of the article successively through the cutaway por- 7 tion of the grinding wheel.

6. The process of grinding a toothed shaft or the like which comprises bringing the valley portions of a toothed shaft or the like into tangential contact with a grinding wheel having a peripheral portion thereof formed with a helical groove to allow the teeth to pass, and arranged with its axis transverse to the axis of the shaft, rotating the shaft about its axis other than by the contact of the wheel with the shaft and in timed relation to the rotation of the wheel to cause the teeth of the shaft to pass successively through the grooved portion of the wheel and moving the shaft longitudinally during the grinding operation to cause the wheel to grind the valley portions of the shaft successively in helical paths.

Signed at Detroit, Michigan, this 2nd day of March, 1923.

FRED J. LAMBORN. 

